| Message ID | 20210108195157.32067-1-peter.maydell@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | target/arm: Don't decode insns in the XScale/iWMMXt space as cp insns | expand |
On 1/8/21 9:51 AM, Peter Maydell wrote: > In commit cd8be50e58f63413c0 we converted the A32 coprocessor > insns to decodetree. This accidentally broke XScale/iWMMXt insns, > because it moved the handling of "cp insns which are handled > by looking up the cp register in the hashtable" from after the > call to the legacy disas_xscale_insn() decode to before it, > with the result that all XScale/iWMMXt insns now UNDEF. > > Update valid_cp() so that it knows that on XScale cp 0 and 1 > are not standard coprocessor instructions; this will cause > the decodetree trans_ functions to ignore them, so that > execution will correctly get through to the legacy decode again. > > Cc: qemu-stable@nongnu.org > Reported-by: Guenter Roeck <linux@roeck-us.net> > Signed-off-by: Peter Maydell <peter.maydell@linaro.org> > --- > With this Guenter's test image now successfully boots > and shuts down again. > --- Reviewed-by: Richard Henderson <richard.henderson@linaro.org> r~
On 1/8/21 11:51 AM, Peter Maydell wrote: > In commit cd8be50e58f63413c0 we converted the A32 coprocessor > insns to decodetree. This accidentally broke XScale/iWMMXt insns, > because it moved the handling of "cp insns which are handled > by looking up the cp register in the hashtable" from after the > call to the legacy disas_xscale_insn() decode to before it, > with the result that all XScale/iWMMXt insns now UNDEF. > > Update valid_cp() so that it knows that on XScale cp 0 and 1 > are not standard coprocessor instructions; this will cause > the decodetree trans_ functions to ignore them, so that > execution will correctly get through to the legacy decode again. > > Cc: qemu-stable@nongnu.org > Reported-by: Guenter Roeck <linux@roeck-us.net> > Signed-off-by: Peter Maydell <peter.maydell@linaro.org> > --- > With this Guenter's test image now successfully boots > and shuts down again. > --- Thanks a lot for the fix! Tested-by: Guenter Roeck <linux@roeck-us.net> > target/arm/translate.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/target/arm/translate.c b/target/arm/translate.c > index f5acd32e76a..528b93dffa2 100644 > --- a/target/arm/translate.c > +++ b/target/arm/translate.c > @@ -5282,7 +5282,14 @@ static bool valid_cp(DisasContext *s, int cp) > * only cp14 and cp15 are valid, and other values aren't considered > * to be in the coprocessor-instruction space at all. v8M still > * permits coprocessors 0..7. > + * For XScale, we must not decode the XScale cp0, cp1 space as > + * a standard coprocessor insn, because we want to fall through to > + * the legacy disas_xscale_insn() decoder after decodetree is done. > */ > + if (arm_dc_feature(s, ARM_FEATURE_XSCALE) && (cp == 0 || cp == 1)) { > + return false; > + } > + > if (arm_dc_feature(s, ARM_FEATURE_V8) && > !arm_dc_feature(s, ARM_FEATURE_M)) { > return cp >= 14; >
diff --git a/target/arm/translate.c b/target/arm/translate.c index f5acd32e76a..528b93dffa2 100644 --- a/target/arm/translate.c +++ b/target/arm/translate.c @@ -5282,7 +5282,14 @@ static bool valid_cp(DisasContext *s, int cp) * only cp14 and cp15 are valid, and other values aren't considered * to be in the coprocessor-instruction space at all. v8M still * permits coprocessors 0..7. + * For XScale, we must not decode the XScale cp0, cp1 space as + * a standard coprocessor insn, because we want to fall through to + * the legacy disas_xscale_insn() decoder after decodetree is done. */ + if (arm_dc_feature(s, ARM_FEATURE_XSCALE) && (cp == 0 || cp == 1)) { + return false; + } + if (arm_dc_feature(s, ARM_FEATURE_V8) && !arm_dc_feature(s, ARM_FEATURE_M)) { return cp >= 14;
In commit cd8be50e58f63413c0 we converted the A32 coprocessor insns to decodetree. This accidentally broke XScale/iWMMXt insns, because it moved the handling of "cp insns which are handled by looking up the cp register in the hashtable" from after the call to the legacy disas_xscale_insn() decode to before it, with the result that all XScale/iWMMXt insns now UNDEF. Update valid_cp() so that it knows that on XScale cp 0 and 1 are not standard coprocessor instructions; this will cause the decodetree trans_ functions to ignore them, so that execution will correctly get through to the legacy decode again. Cc: qemu-stable@nongnu.org Reported-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> --- With this Guenter's test image now successfully boots and shuts down again. --- target/arm/translate.c | 7 +++++++ 1 file changed, 7 insertions(+)